Rhodium‐Catalyzed ON‐OFF Switchable Hydrogenation Using a Molecular Shuttle Based on a [2]Rotaxane with a Phosphine Ligand DOI
Yuping Tang,

Yi‐Er Luo,

Junfeng Xiang

et al.

Angewandte Chemie, Journal Year: 2022, Volume and Issue: 134(15)

Published: Feb. 1, 2022

Abstract A novel pH‐responsive molecular shuttle based on a [2]rotaxane with phosphine ligand has been designed and synthesized. In the rhodium‐catalyzed hydrogenation of α,β‐dehydroamino acid esters aryl enamides, ON/OFF‐switchable catalysis was accomplished high ON/OFF ratios by adjusting movements rotaxane wheels located at catalyst terminals acid/base. Mechanistic studies using NMR spectroscopy quasi in situ X‐ray photoelectron revealed that Rh III ‐hydride species are possibly formed H 2 atmosphere when is OFF state. During reaction, heterolytic activation dihydrogen occurs interlocked dibenzylamine I catalytic center acting as frustrated Lewis pair. Subsequent homolytic splitting newly generates species. These findings show substrate‐selective can be achieved OFF‐state catalyst.

Language: Английский

Selective Arene Hydrogenation for Direct Access to Saturated Carbo‐ and Heterocycles DOI Creative Commons
Mario P. Wiesenfeldt, Zackaria Nairoukh, Toryn Dalton

et al.

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(31), P. 10460 - 10476

Published: Jan. 31, 2019

Arene hydrogenation provides direct access to saturated carbo- and heterocycles thus its strategic application may be used shorten synthetic routes. This powerful transformation is widely applied in industry expected facilitate major breakthroughs the sciences. The ability overcome aromaticity while controlling diastereo-, enantio-, chemoselectivity central use of preparation complex molecules. In general, multisubstituted arenes yields predominantly cis isomer. Enantiocontrol imparted by chiral auxiliaries, Brønsted acids, or transition-metal catalysts. Recent studies have demonstrated that highly chemoselective transformations are possible. Such methods underlying strategies reviewed herein, with an emphasis on synthetically useful examples employ readily available

Language: Английский

Citations

248
Asymmetric Hydrogenation of In Situ Generated Isochromenylium Intermediates by Copper/Ruthenium Tandem Catalysis DOI
Tingting Miao,

Zi‐You Tian,

Yan‐Mei He

et al.

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(15), P. 4135 - 4139

Published: March 15, 2017

Abstract The first asymmetric hydrogenation of in situ generated isochromenylium derivatives is enabled by tandem catalysis with a binary system consisting Cu(OTf) 2 and chiral cationic ruthenium–diamine complex. A range 1 H ‐isochromenes were obtained high yields good to excellent enantioselectivity. These could be easily transformed into isochromanes, which represent an important structural motif natural products biologically active compounds. induction was rationalized density functional theory calculations.

Language: Английский

Citations

60
Die selektive Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen DOI Creative Commons
Mario P. Wiesenfeldt, Zackaria Nairoukh, Toryn Dalton

et al.

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 131(31), P. 10570 - 10586

Published: Jan. 31, 2019

Abstract Die Arenhydrierung bietet einen direkten Zugang zu gesättigten Carbo‐ und Heterocyclen kann daher zur Verkürzung von Synthesewegen genutzt werden. Diese nützliche Transformation wird industriell verwendet sollte weitere Durchbrüche in den angewandten Wissenschaften ermöglichen. Von zentraler Bedeutung für die Anwendung bei der Herstellung komplexer Moleküle ist Kontrolle Diastereo‐, Enantio‐ Chemoselektivität. Im Allgemeinen ergibt Hydrierung multisubstituierter Arene überwiegend das cis‐Isomer. Enantiokontrolle über chirale Auxiliare, Brønsted‐Säuren oder Übergangsmetallkatalysatoren erfolgen. Jüngere Arbeiten zeigen hoch chemoselektive Transformationen. Derartige Verfahren zugrunde liegenden Strategien werden hier erläutert, wobei Schwerpunkt auf präparativ nützlichen Reaktion mit leicht verfügbaren Katalysatoren liegt.

Citations

49
Rhodium‐Catalyzed ON‐OFF Switchable Hydrogenation Using a Molecular Shuttle Based on a [2]Rotaxane with a Phosphine Ligand DOI
Yuping Tang,

Yi‐Er Luo,

Junfeng Xiang

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(15)

Published: Feb. 1, 2022

A novel pH-responsive molecular shuttle based on a [2]rotaxane with phosphine ligand has been designed and synthesized. In the rhodium-catalyzed hydrogenation of α,β-dehydroamino acid esters aryl enamides, ON/OFF-switchable catalysis was accomplished high ON/OFF ratios by adjusting movements rotaxane wheels located at catalyst terminals acid/base. Mechanistic studies using NMR spectroscopy quasi in situ X-ray photoelectron revealed that RhIII -hydride species are possibly formed H2 atmosphere when is OFF state. During reaction, heterolytic activation dihydrogen occurs interlocked dibenzylamine RhI catalytic center acting as frustrated Lewis pair. Subsequent homolytic splitting newly generates species. These findings show substrate-selective can be achieved OFF-state catalyst.

Language: Английский

Citations

20
Enantioselective Hydrogenation of Imidazo[1,2‐a]pyridines DOI
Christoph Schlepphorst, Mario P. Wiesenfeldt, Frank Glorius

et al.

Chemistry - A European Journal, Journal Year: 2017, Volume and Issue: 24(2), P. 356 - 359

Published: Nov. 15, 2017

Abstract The enantioselective synthesis of tetrahydroimidazo[1,2‐ a ]pyridines by direct hydrogenation was achieved using ruthenium/N‐heterocyclic carbene (NHC) catalyst. reaction forgoes the need for protecting or activating groups, proceeds with complete regioselectivity, good to excellent yields, enantiomeric ratios up 98:2, and tolerates broad range functional groups. 5,6,7,8‐Tetrahydroimidazo[1,2‐ ]pyridines, which are found in numerous bioactive molecules, were directly obtained this method, its applicability demonstrated (formal) several molecules.

Language: Английский

Citations

36
Asymmetric Hydrogenation of In Situ Generated Isochromenylium Intermediates by Copper/Ruthenium Tandem Catalysis DOI
Tingting Miao,

Zi‐You Tian,

Yan‐Mei He

et al.

Angewandte Chemie, Journal Year: 2017, Volume and Issue: 129(15), P. 4199 - 4203

Published: March 15, 2017

Abstract The first asymmetric hydrogenation of in situ generated isochromenylium derivatives is enabled by tandem catalysis with a binary system consisting Cu(OTf) 2 and chiral cationic ruthenium–diamine complex. A range 1 H ‐isochromenes were obtained high yields good to excellent enantioselectivity. These could be easily transformed into isochromanes, which represent an important structural motif natural products biologically active compounds. induction was rationalized density functional theory calculations.

Language: Английский

Citations

26
Enantioselective Hydrogenation of Pyrrolo[1,2‐a]pyrazines, Heteroaromatics Containing Two Nitrogen Atoms DOI

Shu‐Bo Hu,

Zhang‐Pei Chen,

Bo Song

et al.

Advanced Synthesis & Catalysis, Journal Year: 2017, Volume and Issue: 359(16), P. 2762 - 2767

Published: June 30, 2017

Abstract An enantioselective iridium‐catalyzed direct hydrogenation of heteroaromatics containing two nitrogen atoms, 3‐substituted pyrrolo[1,2‐ a ]pyrazines, has been successfully achieved, providing facile synthesis optically active 1,2,3,4‐tetrahydropyrrolo[1,2‐ ]pyrazines with up to 96% ee . magnified image

Language: Английский

Citations

22
Rhodium‐Catalyzed ON‐OFF Switchable Hydrogenation Using a Molecular Shuttle Based on a [2]Rotaxane with a Phosphine Ligand DOI
Yuping Tang,

Yi‐Er Luo,

Junfeng Xiang

et al.

Angewandte Chemie, Journal Year: 2022, Volume and Issue: 134(15)

Published: Feb. 1, 2022

Abstract A novel pH‐responsive molecular shuttle based on a [2]rotaxane with phosphine ligand has been designed and synthesized. In the rhodium‐catalyzed hydrogenation of α,β‐dehydroamino acid esters aryl enamides, ON/OFF‐switchable catalysis was accomplished high ON/OFF ratios by adjusting movements rotaxane wheels located at catalyst terminals acid/base. Mechanistic studies using NMR spectroscopy quasi in situ X‐ray photoelectron revealed that Rh III ‐hydride species are possibly formed H 2 atmosphere when is OFF state. During reaction, heterolytic activation dihydrogen occurs interlocked dibenzylamine I catalytic center acting as frustrated Lewis pair. Subsequent homolytic splitting newly generates species. These findings show substrate‐selective can be achieved OFF‐state catalyst.

Language: Английский

Citations

4